U.S. Pat. No. 5,827,565 provides that most dogs enjoy chewing on various objects, although preferences vary as to the desired hardness of those objects. Some dogs like to chew on very hard materials such as cow bones, wood, nylon, and the like. Some dogs, due to their age, may not be able to chew on very hard substances. Young dogs may have insufficiently developed teeth, while older dogs may have diseased gums or may have lost some of their teeth.
The prior art is replete with examples of hard chews, soft chews, indigestible chews, and digestible chews. All of these prior art animal chews, however, rely exclusive on mechanical action, i.e. the animal's chewing action, to assist in removal of plaque from the animal's teeth.
For example, Applicant's assignee, T.F.H. Publications, Inc. has previously developed an edible dog chew that is wholly digestible, nutritious and maintains a texture or hardness which is individually adjustable by application of heat to suit a wide variety of preferences or needs. Such dog chews utilize a mixture of primarily casein and are described in U.S. Pat. Nos. 5,200,212 and 5,240,720.
In Applicant's U.S. Pat. No. 5,827,565 there is disclosed a process for making a heat expandable dog chew comprised primarily of injection molded potato starch granules and an attractant. Attractants recited include chicken powder, liver powder, ham, turkey, beef and/or fish. Natural vegetable additives such as spinach or carrots may also be added.
In Applicant's U.S. patent application Ser. No. 09/138,804, which as noted is a continuation-in-part of U.S. Pat. No. 5,827,565, there is disclosed a dog chew having natural fruit flavor to increase the dog's appetite for such chew. The preferred form of such edible chew maintained the basic ingredient of a heat-expandable starch, such as potato starch.
Attention is also directed to the following U.S. patents and copending applications, commonly owned by the assignee herein: U.S. Pat. No. 5,476,069; U.S. patent application Ser. No. 08/923,070 filed Sep. 3, 1997 entitled "Vegetable Based Dog Chew"; Ser. No. 08/738,423 filed Oct. 25, 1997 entitled "Edible Dog Chew"; Ser. No. 08/784,834 filed Jan. 17, 1997 entitled "Carrot-Based Dog Chew"; Ser. No. 08/888,611 filed Jul. 7, 1997 entitled "Vegetable Dog Chew"; Ser. No. 09/114,872 filed Jul. 14, 1998 entitled "Heat Modifiable Edible Dog Chew"; Ser. No. 09/138,804 filed Aug. 21, 1998 entitled "Improved Edible Dog Chew"; Ser. No. 09/116,070 filed Jul. 15, 1998 entitled "Wheat & Casein Dow Chew With Modifiable Texture"; Ser. No. 09/116,555 filed Jul. 15, 1998 entitled "Heat Modifiable Peanut Dog Chew"; Ser. No. 09/227,767 filed Jan. 8, 1999 entitled "Method of Molding Edible Starch." In addition to such patents and applications, attention is also directed to the art cited in said patents and applications, as such art relates to the field of molded starch products.
In addition, the prior art has recently grown to include a variety of other disclosures directed at flavored pet products. For example, U.S. Pat. No. 5,786,382 entitled "Use of Valerian Plant and/or Root as a Scent-Attractant for Stimulating Canine and Felines." This patent discloses the use of the herb/plant Valerian in all of its forms, whether whole or in part, for use in a food product, whereby the natural aroma emitted by the Valerian plant will attract dogs and cats.
U.S. Pat. Nos. 4,985,964 and 5,007,879 entitled "Dog Chew Processing Method" disclose methods for processing cattle hoofs for use as a dog chew product. U.S. Pat. No. 5,149,550 entitled "Methods for Making Pet Chews" discloses that ligaments from cattle and other hoofstocks are rendered substantially free of fat and can be dried and hardened for use as a pet chew.
U.S. Pat. No. 5,407,661 entitled "Pet Chew Product Having Oral Care Properties" discloses an edible pet chew product having a flexible cellular matrix in which is contained cellulosic fibrous material such as corn cob fractions which are described as having a mechanical cleansing function when chewed by a pet.
U.S. Pat. No. 5,635,237 entitled "Method of Manufacturing Substantially Pure Rawhide Pet Products" discloses a chew of pure rawhide utilizing twin screw extrusion with multiple heating zones and interchangeable extrusion dies.
U.S. Pat. No. 5,711,254 entitled "Dog Chew Toy" discloses a chew toy for dogs formed of a length of composite rope having an inner core defined by strands of twisted threads of natural plant or synthetic fibers and a soft outer shell defined by a plurality of strands of soft cotton threads twisted about the inner core. The inner core is said to be less water absorbent than the outer shell to promote drying of the toy when wetted with dog saliva to inhibit bacteria growth.
U.S. Pat. No. 5,750,196 entitled "Process for Manufacturing Dog Chew Toys of Tire Sidewalls" discloses the use of a dye to cut toy bases from sidewalls recovered from used tires.
Other earlier examples of such products are disclosed in U.S. Pat. No. 3,871,334 to Axelrod (nylon substrate containing liquid flavor and odor components), U.S. Pat. No. 4,771,733 to Axelrod (polyurethane toy containing aqueous-based flavor and odor components), and U.S. Pat. Nos. 4,557,219 and 4,513,014 to Edwards (use of flavorings in a molded polyurethane dog chew).
In U.S. Pat. No. 4,691,718, Sakuma et al. disclose a toothbrush molded from an ion eluting-type ceramic and containing a battery. During use a circuit is formed via the user's hand, arm, and body thereby releasing calcium or fluoride ions.
In U.S. Pat. No. 4,969,868, Wang discloses a tooth brush containing a battery and wherein certain special bristles act as a cathode. A metal plate adjacent to the brush head serves as an anode. Use of ionized toothpaste completes the circuit such that current flows.
In U.S. Pat. No. 5,138,733, Bock discloses a toothbrush which generates ultrasonic sound waves. These ultrasonic sound waves assist in plaque removal from the user's teeth.
The animal chew products disclosed previously utilize mechanical energy alone, i.e. the animal's chewing action, to remove plaque from the animals' teeth and to strengthen the animals gums. Accordingly, it is an object herein to improve further upon these prior art pet chew products. Specifically, it is also an object herein to utilize the flow of electricity across a pet chew product to strengthen an animals' teeth and gums. It is a further object herein to utilize the release of certain trace elements and/or ions from a pet chew product to strengthen an animal's teeth. Furthermore, it is an object herein to utilize ultrasonic sound waves generated within a pet chew product to assist cleansing an animal's teeth and gums.